The field of the invention is that of bakery trays, for use with a bakery that will produce a variety of bakery products, of different heights. The baked products are placed in trays for storage and transport, and sometimes also for cooling. The trays usually only carry a single layer of bakery products, are rectangular, and dimensioned so that in one plane a fixed plurality may be placed to fill a truck having standard interior dimensions. The bakery products are shipped in the trays to a distribution center or user, and empty trays are placed in trucks for a return trip to the bakery.
Commercially used bakeries trays have been generally of four types, with some bakerys using more than one type of tray.
TYPE I: A plurality of wire trays or shelves are inserted at selected spacings in a rigid frame having opposed shelf supports. This system is very inflexible, in that it is difficult to place the entire frame in a truck, or the trays must be removed from the bakery frame and inserted into truck frames. Also, the frames are of a fixed height and take up just as much room empty as they do full.
TYPE II: Plastic trays replaced the wire trays or shelves. This reduced cost and weight, but still required the rigid frames and had the above-mentioned disadvantages of the first type of bakery product trays.
TYPE III: Plastic trays were designed to be stackable upon themselves, so that the above-mentioned rigid frames could be eliminated. These trays have gained wide acceptance. They may be rotated 90.degree. when empty to assume a low nest position to conserve space when stored or being returned. This type of tray has a fixed stack height, which is designed to be the highest stack height for their usage, and if they are used for smaller bakery products, vertical space will be wasted accordingly. A tray of this type is disclosed in U.S. Pat. Des. No. 211,068, Miles, May 14, 1968.
TYPE IV: Two or more stacking levels have been obtained with bakery trays by employing bails. These bails, usually metal, may flip and/or slide to assume different vertical positions for supporting an upper tray at correspondingly different vertical stack positions. The trays may nest in one position of the bails or 90.degree. nesting may be employed. An example of such a basket is disclosed in U.S. Pat. No. 4,391,369, Stahl et al, July 6, 1983. While this type of basket is capable of self support in a stack, with a plurality of levels, it has not gained wide commercial usage. The moving parts greatly increase the cost of the basket (perhaps two or three times the cost of a one piece basket of TYPE III). Also, the moving parts give the appearance of unreliability and may in fact have a reliability problem. Also, the moving parts greatly complicate the design, construction and maintenance of automatic handling equipment, particularly conveying equipment used in modern bakeries.